The present invention relates to the structure of a module to be incorporated, for example, into an electronic timepiece, and to electronic devices including such module.
A circuit board is incorporated into a module for an electronic timepiece. The circuit board includes a glass epoxy board on which a circuit pattern is formed by printing. In order to connect the circuit board to another member such as a battery incorporated into a module or still another member such as a piezoelectric element incorporated into the body of the timepiece, connection members such as conductive coil springs and/or conductive plates are required. Thus, many parts are contained in the module and are troublesome to assemble.
The applicants have filed a Japanese patent application Hei 6-274689 for a module in which a connection member such as the coil spring was mentioned above is eliminated by fabricating a circuit board using a metal core (this application was published May 31, 1996; publication No. 8-136673).
This module mainly comprises the circuit board, which has a metal core covered with an insulating layer on which a circuit pattern is formed and covered with a resist layer.
The circuit board is held fixedly between an upper and a lower insulating housing. This circuit board and a liquid crystal display member are connected by an interconnector.
Such module is generally assembled using a baseplate. The baseplate assembles the upper and lower housings thereon and maintains the assembled state of the module.
In addition, the baseplate is also used as a switching member. In the case of an electronic timepiece in which such module is provided, in order to transmit to the circuit board the depression of a push button provided on the timepiece body to switch among function of the timepiece, a movable plate-like contact attached to the baseplate is required to be disposed between the push button and the circuit board.
In a module structure of the type mentioned above, in order to ensure proper assembly and to enable use as a switching member, the ground plate is a necessary element that cannot be eliminated. Therefore, the number of parts of the module would increase accordingly to complicate the module structure and the module is troublesome to assemble. In addition, the module would increase in thickness by a quantity corresponding to the thickness of the baseplate.
The present invention intends to eliminate such problems. More specifically, it is an object of the present invention to provide a module structure which can be assembled without using a baseplate and which has a reduced number of components and thinned structure, and an electronic device having such module structure.
In order to achieve the above object, the present invention provides a module structure comprising a circuit board and a pair of housings between which the circuit board is disposed, the circuit board comprising a metal core; an insulating layer disposed on the core so as to cover same; a plurality of circuits formed on the insulating layer; and first engaging means. In addition, at least one of the housings includes second engaging means formed thereon so as to be engaged with the first engaging means for fixing the circuit board to that housing.
The present invention also provides an electronic device comprising a body and a module attached to the body, the module comprising a circuit board and a plurality of housings between which the circuit board is disposed, the circuit board comprising a metal core; an insulating layer disposed on the core so as to cover same; a plurality of circuits formed on the insulating layer; and first engaging means. In addition, at least one of the housings includes second engaging means formed thereon so as to be engaged with the first engaging means for fixing the circuit board to that housing.